Final answer:
Using high-quality motor oil can improve fuel economy by up to 5%.
Step-by-step explanation:
The most likely fact that can be inferred from the ad is that using high-quality motor oil can improve fuel economy by up to 5%. Although the ad is promoting Highway Motors' motor oil, it doesn't explicitly state that their oil is high-quality. However, it suggests that their oil can improve fuel economy, which implies it is of good quality.
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